Bob/backend list (#1220)

* open only the unversioned library but check that it is built against the correct version of ngraph

* review comments

src/ngraph/CMakeLists.txt

@@ -178,10 +178,10 @@ add_subdirectory(codegen)
 add_subdirectory(runtime)
 
 add_library(ngraph SHARED ${SRC})
-add_definitions("-DSHARED_LIB_EXT=\"${CMAKE_SHARED_LIBRARY_SUFFIX}\"")
-add_definitions("-DLIBRARY_VERSION=\"${NGRAPH_VERSION}\"")
+target_compile_definitions(ngraph PRIVATE SHARED_LIB_EXT="${CMAKE_SHARED_LIBRARY_SUFFIX}")
 set_target_properties(ngraph PROPERTIES VERSION ${NGRAPH_VERSION} SOVERSION ${NGRAPH_API_VERSION})
 target_link_libraries(ngraph PUBLIC libjson)
+target_compile_definitions(ngraph PUBLIC NGRAPH_VERSION="${NGRAPH_VERSION}")
 
 if (NGRAPH_ONNX_IMPORT_ENABLE)
     add_dependencies(ngraph onnx_import)

src/ngraph/file_util.cpp

@@ -213,7 +213,8 @@ string file_util::read_file_to_string(const string& path)
 
 static void iterate_files_worker(const string& path,
                                  function<void(const string& file, bool is_dir)> func,
-                                 bool recurse)
+                                 bool recurse,
+                                 bool include_links)
 {
     DIR* dir;
     struct dirent* ent;
@@ -224,26 +225,26 @@ static void iterate_files_worker(const string& path,
             while ((ent = readdir(dir)) != nullptr)
             {
                 string name = ent->d_name;
+                string path_name = file_util::path_join(path, name);
                 switch (ent->d_type)
                 {
                 case DT_DIR:
                     if (name != "." && name != "..")
                     {
-                        string dir_path = file_util::path_join(path, name);
                         if (recurse)
                         {
-                            file_util::iterate_files(dir_path, func, recurse);
+                            file_util::iterate_files(path_name, func, recurse);
                         }
-                        func(dir_path, true);
+                        func(path_name, true);
                     }
                     break;
-                case DT_LNK: break;
-                case DT_REG:
-                {
-                    string file_name = file_util::path_join(path, name);
-                    func(file_name, false);
+                case DT_LNK:
+                    if (include_links)
+                    {
+                        func(path_name, false);
+                    }
                     break;
-                }
+                case DT_REG: func(path_name, false); break;
                 default: break;
                 }
             }
@@ -264,7 +265,8 @@ static void iterate_files_worker(const string& path,
 
 void file_util::iterate_files(const string& path,
                               function<void(const string& file, bool is_dir)> func,
-                              bool recurse)
+                              bool recurse,
+                              bool include_links)
 {
     vector<string> files;
     vector<string> dirs;
@@ -279,7 +281,8 @@ void file_util::iterate_files(const string& path,
                                  files.push_back(file);
                              }
                          },
-                         recurse);
+                         recurse,
+                         include_links);
 
     for (auto f : files)
     {

src/ngraph/file_util.hpp

@@ -79,7 +79,8 @@ namespace ngraph
         // @param recurse Optional parameter to enable recursing through path
         void iterate_files(const std::string& path,
                            std::function<void(const std::string& file, bool is_dir)> func,
-                           bool recurse = false);
+                           bool recurse = false,
+                           bool include_links = false);
 
         // @brief Create a temporary file
         // @param extension Optional extension for the temporary file

src/ngraph/runtime/backend.cpp

@@ -15,6 +15,7 @@
 *******************************************************************************/
 
 #include <dlfcn.h>
+#include <regex>
 #include <sstream>
 
 #include "ngraph/file_util.hpp"
@@ -37,22 +38,9 @@ static string find_my_file()
     return dl_info.dli_fname;
 }
 
-// This will be uncommented when we add support for listing all known backends
-// static bool is_backend(const string& path)
-// {
-//     bool rc = false;
-//     string name = file_util::get_file_name(path);
-//     if (name.find("_backend.") != string::npos)
-//     {
-//         NGRAPH_INFO << name;
-//     }
-//     return rc;
-// }
-
 void* runtime::Backend::open_shared_library(string type)
 {
     string ext = SHARED_LIB_EXT;
-    string ver = LIBRARY_VERSION;
 
     void* handle = nullptr;
 
@@ -62,16 +50,12 @@ void* runtime::Backend::open_shared_library(string type)
     {
         type = type.substr(0, colon);
     }
-    string lib_name = "lib" + to_lower(type) + "_backend" + ext;
+
+    string library_name = "lib" + to_lower(type) + "_backend" + string(SHARED_LIB_EXT);
     string my_directory = file_util::get_directory(find_my_file());
-    string full_path = file_util::path_join(my_directory, lib_name);
-    handle = dlopen(full_path.c_str(), RTLD_NOW | RTLD_GLOBAL);
-    if (!handle)
-    {
-        string err = dlerror();
-        throw runtime_error("Library open for Backend '" + lib_name + "' failed with error:\n" +
-                            err);
-    }
+    string library_path = file_util::path_join(my_directory, library_name);
+    handle = dlopen(library_path.c_str(), RTLD_NOW | RTLD_GLOBAL);
+
     return handle;
 }
 
@@ -85,6 +69,15 @@ shared_ptr<runtime::Backend> runtime::Backend::create(const string& type)
     }
     else
     {
+        function<const char*()> get_ngraph_version_string =
+            reinterpret_cast<const char* (*)()>(dlsym(handle, "get_ngraph_version_string"));
+        if (!get_ngraph_version_string)
+        {
+            dlclose(handle);
+            throw runtime_error("Backend '" + type +
+                                "' does not implement get_ngraph_version_string");
+        }
+
         function<runtime::Backend*(const char*)> new_backend =
             reinterpret_cast<runtime::Backend* (*)(const char*)>(dlsym(handle, "new_backend"));
         if (!new_backend)
@@ -110,9 +103,50 @@ shared_ptr<runtime::Backend> runtime::Backend::create(const string& type)
     return rc;
 }
 
+map<string, string> runtime::Backend::get_registered_device_map()
+{
+    map<string, string> rc;
+    string my_directory = file_util::get_directory(find_my_file());
+    vector<string> backend_list;
+    regex reg("^lib(.+)_backend" + string(SHARED_LIB_EXT));
+    smatch result;
+
+    auto f = [&](const string& file, bool is_dir) {
+        string name = file_util::get_file_name(file);
+        if (regex_match(name, result, reg))
+        {
+            auto handle = dlopen(file.c_str(), RTLD_LAZY | RTLD_LOCAL);
+            if (handle)
+            {
+                if (dlsym(handle, "new_backend") && dlsym(handle, "delete_backend"))
+                {
+                    function<const char*()> get_ngraph_version_string =
+                        reinterpret_cast<const char* (*)()>(
+                            dlsym(handle, "get_ngraph_version_string"));
+                    if (get_ngraph_version_string &&
+                        get_ngraph_version_string() == string(NGRAPH_VERSION))
+                    {
+                        rc.insert({to_upper(result[1]), file});
+                    }
+                }
+
+                dlclose(handle);
+            }
+        }
+    };
+    file_util::iterate_files(my_directory, f, false, true);
+    return rc;
+}
+
 vector<string> runtime::Backend::get_registered_devices()
 {
-    return vector<string>();
+    map<string, string> m = get_registered_device_map();
+    vector<string> rc;
+    for (const pair<string, string>& p : m)
+    {
+        rc.push_back(p.first);
+    }
+    return rc;
 }
 
 void runtime::Backend::remove_compiled_function(shared_ptr<Function> func)

src/ngraph/runtime/backend.hpp

@@ -84,6 +84,7 @@ namespace ngraph
 
         private:
             static void* open_shared_library(std::string type);
+            static std::map<std::string, std::string> get_registered_device_map();
         };
     }
 }

src/ngraph/runtime/cpu/cpu_backend.cpp

@@ -26,6 +26,11 @@
 using namespace ngraph;
 using namespace std;
 
+extern "C" const char* get_ngraph_version_string()
+{
+    return NGRAPH_VERSION;
+}
+
 extern "C" runtime::Backend* new_backend(const char* configuration_string)
 {
     // Force TBB to link to the backend

src/ngraph/runtime/gpu/gpu_backend.cpp

@@ -23,6 +23,11 @@
 using namespace ngraph;
 using namespace std;
 
+extern "C" const char* get_ngraph_version_string()
+{
+    return NGRAPH_VERSION;
+}
+
 extern "C" runtime::Backend* new_backend(const char* configuration_string)
 {
     return new runtime::gpu::GPU_Backend();

src/ngraph/runtime/intelgpu/intelgpu_backend.cpp

@@ -20,6 +20,11 @@
 using namespace std;
 using namespace ngraph;
 
+extern "C" const char* get_ngraph_version_string()
+{
+    return NGRAPH_VERSION;
+}
+
 extern "C" runtime::Backend* new_backend(const char* configuration_string)
 {
     return new runtime::intelgpu::IntelGPUBackend();

src/ngraph/runtime/interpreter/int_backend.cpp

@@ -29,6 +29,11 @@ using namespace ngraph;
 
 using descriptor::layout::DenseTensorViewLayout;
 
+extern "C" const char* get_ngraph_version_string()
+{
+    return NGRAPH_VERSION;
+}
+
 extern "C" runtime::Backend* new_backend(const char* configuration_string)
 {
     return new runtime::interpreter::INTBackend();

src/ngraph/util.cpp

@@ -93,6 +93,13 @@ std::string ngraph::to_lower(const std::string& s)
     return rc;
 }
 
+std::string ngraph::to_upper(const std::string& s)
+{
+    std::string rc = s;
+    std::transform(rc.begin(), rc.end(), rc.begin(), ::toupper);
+    return rc;
+}
+
 string ngraph::trim(const string& s)
 {
     string rc = s;

src/ngraph/util.hpp

@@ -110,6 +110,7 @@ namespace ngraph
     void dump(std::ostream& out, const void*, size_t);
 
     std::string to_lower(const std::string& s);
+    std::string to_upper(const std::string& s);
     std::string trim(const std::string& s);
     std::vector<std::string> split(const std::string& s, char delimiter, bool trim = false);
 

test/backend_api.cpp

@@ -27,7 +27,7 @@ TEST(backend_api, registered_devices)
     vector<string> devices = runtime::Backend::get_registered_devices();
     EXPECT_GE(devices.size(), 0);
 
-    // EXPECT_TRUE(contains(devices, "INTERPRETER"));
+    EXPECT_TRUE(contains(devices, "INTERPRETER"));
 }
 
 TEST(backend_api, invalid_name)